diff --git a/core/java/android/net/NetworkAgent.java b/core/java/android/net/NetworkAgent.java
index a4717a1..e9bcefe 100644
--- a/core/java/android/net/NetworkAgent.java
+++ b/core/java/android/net/NetworkAgent.java
@@ -624,7 +624,9 @@
             throw new UnsupportedOperationException(
                     "Legacy agents can't call markConnected.");
         }
-        mNetworkInfo.setDetailedState(NetworkInfo.DetailedState.CONNECTED, null, null);
+        // |reason| cannot be used by the non-legacy agents
+        mNetworkInfo.setDetailedState(NetworkInfo.DetailedState.CONNECTED, null /* reason */,
+                mNetworkInfo.getExtraInfo());
         queueOrSendMessage(EVENT_NETWORK_INFO_CHANGED, mNetworkInfo);
     }
 
@@ -638,7 +640,9 @@
         if (mIsLegacy) {
             throw new UnsupportedOperationException("Legacy agents can't call unregister.");
         }
-        mNetworkInfo.setDetailedState(NetworkInfo.DetailedState.DISCONNECTED, null, null);
+        // When unregistering an agent nobody should use the extrainfo (or reason) any more.
+        mNetworkInfo.setDetailedState(NetworkInfo.DetailedState.DISCONNECTED, null /* reason */,
+                null /* extraInfo */);
         queueOrSendMessage(EVENT_NETWORK_INFO_CHANGED, mNetworkInfo);
     }
 
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 0c45285..ea91395 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -3144,7 +3144,7 @@
             }
         }
 
-        nai.clatd.setNat64Prefix(prefix);
+        nai.clatd.setNat64PrefixFromDns(prefix);
         handleUpdateLinkProperties(nai, new LinkProperties(nai.linkProperties));
     }
 
@@ -5856,9 +5856,9 @@
             @NonNull LinkProperties oldLp) {
         int netId = networkAgent.network.netId;
 
-        // The NetworkAgentInfo does not know whether clatd is running on its network or not, or
-        // whether there is a NAT64 prefix. Before we do anything else, make sure its LinkProperties
-        // are accurate.
+        // The NetworkAgent does not know whether clatd is running on its network or not, or whether
+        // a NAT64 prefix was discovered by the DNS resolver. Before we do anything else, make sure
+        // the LinkProperties for the network are accurate.
         networkAgent.clatd.fixupLinkProperties(oldLp, newLp);
 
         updateInterfaces(newLp, oldLp, netId, networkAgent.networkCapabilities,
diff --git a/services/core/java/com/android/server/connectivity/Nat464Xlat.java b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
index 82465f8..741cb5b 100644
--- a/services/core/java/com/android/server/connectivity/Nat464Xlat.java
+++ b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
@@ -81,7 +81,7 @@
         RUNNING,      // start() called, and the stacked iface is known to be up.
     }
 
-    private IpPrefix mNat64Prefix;
+    private IpPrefix mNat64PrefixFromDns;
     private String mBaseIface;
     private String mIface;
     private Inet6Address mIPv6Address;
@@ -100,7 +100,7 @@
      * currently connected and where the NetworkAgent has not disabled 464xlat. It is the signal to
      * enable NAT64 prefix discovery.
      *
-     * @param network the NetworkAgentInfo corresponding to the network.
+     * @param nai the NetworkAgentInfo corresponding to the network.
      * @return true if the network requires clat, false otherwise.
      */
     @VisibleForTesting
@@ -180,7 +180,7 @@
 
         String addrStr = null;
         try {
-            addrStr = mNetd.clatdStart(baseIface, mNat64Prefix.toString());
+            addrStr = mNetd.clatdStart(baseIface, getNat64Prefix().toString());
         } catch (RemoteException | ServiceSpecificException e) {
             Slog.e(TAG, "Error starting clatd on " + baseIface + ": " + e);
         }
@@ -213,12 +213,10 @@
         }
         mIface = null;
         mBaseIface = null;
-        mState = State.IDLE;
         if (requiresClat(mNetwork)) {
             mState = State.DISCOVERING;
         } else {
             stopPrefixDiscovery();
-            mState = State.IDLE;
         }
     }
 
@@ -285,6 +283,7 @@
     private void stopPrefixDiscovery() {
         try {
             mDnsResolver.stopPrefix64Discovery(getNetId());
+            mState = State.IDLE;
         } catch (RemoteException | ServiceSpecificException e) {
             Slog.e(TAG, "Error stopping prefix discovery on netId " + getNetId() + ": " + e);
         }
@@ -294,32 +293,52 @@
      * Starts/stops NAT64 prefix discovery and clatd as necessary.
      */
     public void update() {
-        // TODO: turn this class into a proper StateMachine. // http://b/126113090
-        if (requiresClat(mNetwork)) {
-            if (!isPrefixDiscoveryStarted()) {
-                startPrefixDiscovery();
-            } else if (shouldStartClat(mNetwork)) {
-                // NAT64 prefix detected. Start clatd.
-                // TODO: support the NAT64 prefix changing after it's been discovered. There is no
-                // need to support this at the moment because it cannot happen without changes to
-                // the Dns64Configuration code in netd.
-                start();
-            } else {
-                // NAT64 prefix removed. Stop clatd and go back into DISCOVERING state.
-                stop();
-            }
-        } else {
-            // Network no longer requires clat. Stop clat and prefix discovery.
-            if (isStarted()) {
-                stop();
-            } else if (isPrefixDiscoveryStarted()) {
-                leaveStartedState();
-            }
+        // TODO: turn this class into a proper StateMachine. http://b/126113090
+        switch (mState) {
+            case IDLE:
+                if (requiresClat(mNetwork)) {
+                    // Network is detected to be IPv6-only.
+                    // TODO: consider going to STARTING directly if the NAT64 prefix is already
+                    // known. This would however result in clatd running without prefix discovery
+                    // running, which might be a surprising combination.
+                    startPrefixDiscovery();  // Enters DISCOVERING state.
+                    return;
+                }
+                break;
+
+            case DISCOVERING:
+                if (shouldStartClat(mNetwork)) {
+                    // NAT64 prefix detected. Start clatd.
+                    start();  // Enters STARTING state.
+                    return;
+                }
+                if (!requiresClat(mNetwork)) {
+                    // IPv4 address added. Go back to IDLE state.
+                    stopPrefixDiscovery();
+                    return;
+                }
+                break;
+
+            case STARTING:
+            case RUNNING:
+                // NAT64 prefix removed, or IPv4 address added.
+                // Stop clatd and go back into DISCOVERING or idle.
+                if (!shouldStartClat(mNetwork)) {
+                    stop();
+                }
+                break;
+                // TODO: support the NAT64 prefix changing after it's been discovered. There is
+                // no need to support this at the moment because it cannot happen without
+                // changes to the Dns64Configuration code in netd.
         }
     }
 
-    public void setNat64Prefix(IpPrefix nat64Prefix) {
-        mNat64Prefix = nat64Prefix;
+    private IpPrefix getNat64Prefix() {
+        return mNat64PrefixFromDns;
+    }
+
+    public void setNat64PrefixFromDns(IpPrefix prefix) {
+        mNat64PrefixFromDns = prefix;
     }
 
     /**
@@ -328,7 +347,7 @@
      * has no idea that 464xlat is running on top of it.
      */
     public void fixupLinkProperties(@NonNull LinkProperties oldLp, @NonNull LinkProperties lp) {
-        lp.setNat64Prefix(mNat64Prefix);
+        lp.setNat64Prefix(getNat64Prefix());
 
         if (!isRunning()) {
             return;
diff --git a/tests/net/common/java/android/net/NetworkCapabilitiesTest.java b/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
index 316a83a..6e9dc8e 100644
--- a/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
+++ b/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
@@ -55,6 +55,10 @@
 import androidx.core.os.BuildCompat;
 import androidx.test.runner.AndroidJUnit4;
 
+import com.android.testutils.DevSdkIgnoreRule;
+import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
+
+import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -67,6 +71,9 @@
     private static final String TEST_SSID = "TEST_SSID";
     private static final String DIFFERENT_TEST_SSID = "DIFFERENT_TEST_SSID";
 
+    @Rule
+    public DevSdkIgnoreRule mDevSdkIgnoreRule = new DevSdkIgnoreRule();
+
     private boolean isAtLeastR() {
         // BuildCompat.isAtLeastR() is used to check the Android version before releasing Android R.
         // Build.VERSION.SDK_INT > Build.VERSION_CODES.Q is used to check the Android version after
@@ -441,7 +448,7 @@
         return range;
     }
 
-    @Test
+    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
     public void testSetAdministratorUids() {
         NetworkCapabilities nc =
                 new NetworkCapabilities().setAdministratorUids(new int[] {2, 1, 3});
@@ -449,7 +456,7 @@
         assertArrayEquals(new int[] {1, 2, 3}, nc.getAdministratorUids());
     }
 
-    @Test
+    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
     public void testSetAdministratorUidsWithDuplicates() {
         try {
             new NetworkCapabilities().setAdministratorUids(new int[] {1, 1});
@@ -510,6 +517,12 @@
         assertFalse(nc2.appliesToUid(12));
         assertTrue(nc1.appliesToUid(22));
         assertTrue(nc2.appliesToUid(22));
+    }
+
+    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
+    public void testCombineCapabilities_AdministratorUids() {
+        final NetworkCapabilities nc1 = new NetworkCapabilities();
+        final NetworkCapabilities nc2 = new NetworkCapabilities();
 
         final int[] adminUids = {3, 6, 12};
         nc1.setAdministratorUids(adminUids);
@@ -518,7 +531,7 @@
         assertArrayEquals(nc2.getAdministratorUids(), adminUids);
 
         final int[] adminUidsOtherOrder = {3, 12, 6};
-        nc1.setAdministratorUids(adminUids);
+        nc1.setAdministratorUids(adminUidsOtherOrder);
         assertTrue(nc2.equalsAdministratorUids(nc1));
 
         final int[] adminUids2 = {11, 1, 12, 3, 6};
diff --git a/tests/net/java/com/android/server/connectivity/Nat464XlatTest.java b/tests/net/java/com/android/server/connectivity/Nat464XlatTest.java
index 9b24887..d0ebb52 100644
--- a/tests/net/java/com/android/server/connectivity/Nat464XlatTest.java
+++ b/tests/net/java/com/android/server/connectivity/Nat464XlatTest.java
@@ -181,7 +181,7 @@
         Nat464Xlat nat = makeNat464Xlat();
         ArgumentCaptor<LinkProperties> c = ArgumentCaptor.forClass(LinkProperties.class);
 
-        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+        nat.setNat64PrefixFromDns(new IpPrefix(NAT64_PREFIX));
 
         // Start clat.
         nat.start();
@@ -222,7 +222,7 @@
         ArgumentCaptor<LinkProperties> c = ArgumentCaptor.forClass(LinkProperties.class);
         InOrder inOrder = inOrder(mNetd, mConnectivity);
 
-        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+        nat.setNat64PrefixFromDns(new IpPrefix(NAT64_PREFIX));
 
         nat.start();
 
@@ -309,7 +309,7 @@
         Nat464Xlat nat = makeNat464Xlat();
         ArgumentCaptor<LinkProperties> c = ArgumentCaptor.forClass(LinkProperties.class);
 
-        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+        nat.setNat64PrefixFromDns(new IpPrefix(NAT64_PREFIX));
 
         nat.start();
 
@@ -348,7 +348,7 @@
     public void testStopBeforeClatdStarts() throws Exception {
         Nat464Xlat nat = makeNat464Xlat();
 
-        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+        nat.setNat64PrefixFromDns(new IpPrefix(NAT64_PREFIX));
 
         nat.start();
 
@@ -380,7 +380,7 @@
     public void testStopAndClatdNeverStarts() throws Exception {
         Nat464Xlat nat = makeNat464Xlat();
 
-        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+        nat.setNat64PrefixFromDns(new IpPrefix(NAT64_PREFIX));
 
         nat.start();